Five days old B. zonata pupae were subjected to gamma irradiation at doses of 25, 30, 35 and 50 Gray (Gy), from a Cesium cell-137. The resulting males were crossed with untreated females. The mean total number of eggs laid by the female (fecundity) is significantly decreased (P < 0.05) with the dose increase. The viability (hatching percent) of deposited eggs at all three doses showed a significant decrease (P < 0.05). Laid eggs by females mated with males resulted from pupae treated with gamma radiation with doses 25,30,35 and 50 Gy were processed for histological studies. First cleavage nuclei were observed about 2 hours pop and the blastoderm formation occur about 4 hours pop in control. At 8 hours pop, the blastoderm thickness forming the germ band. In about 24 hours pop brain appeared. The germ band Segmentation and formation of different organs started about 36hrs POP. Doses of 25 and 30 caused a failure of cleavage nuclei to migrate toward the periphery to form the blastoderm. While other embryos were blocked at germ band formation. In doses of 35 and 50 Gy, massive cellular and tissue damage to the embryos was reported.